1. Field of the Invention
The present invention relates to a backlight module, and particularly to a backlight module with side fixing frames to contain lamp assemblies and fasten a stack assembly including a supporting frame, a reflecting plate and a light guiding plate.
2. Description of the Prior Art
As semiconductor fabrication technologies are rapidly advanced, display devices are required to be lighter, smaller and slimmer. This is especially the true for flat panel display devices such as liquid crystal displays and plasma displays. Therefore, the industry endeavors in reducing the assembly elements and the process to the extent possible.
LCD monitors are widely used in desktop computers and notebook computers. An LCD panel assembly and a backlight module are respectively assembled using separate assembly processes before both are assembled together. FIG. 1 is a conventional backlight assembly. The components of the liquid crystal display device such as a reflecting plate, a light guiding plate, a diffusing film and lamp assembly are assembled together between an upper frame 100 with a central opening and a supporting frame 200. There are several engaging elements 101 on the edges of the upper frame 100 to couple with counterparts 201 on the edges of the supporting frame 200 so that the above components are fastened and secured. Making liquid crystal display devices lighter and slimmer causes the upper frame 100 to be made too soft and results in the difficulty of mold injection. Furthermore, cost increases because the structure and assembly become more complicated.
U.S. Pat. No. 6,502,945B2 discloses a stack type backlight module and an assembly method thereof. The stack type backlight module includes a mold frame, a reflecting plate, a light guiding plate placed on the reflecting plate, a pair of lamp assemblies respectively accommodated on each side portion of the light guiding plate, diffusing plates placed on the light guide and a pair of fixing frames facing each other covering the edge of the light guiding plate, and being detachably coupled to the mold frame.
U.S. Pat. No. 6,502,945B2 utilizes two L-shaped mold frames and a supporting frame to serve as a support for assembling other components. The L-shaped mold frames are coupled with the supporting frame to fasten the other components. Therefore, the whole structure of the stack type backlight module is more complicated.
Moreover, the components of the stack type backlight module must be put together from top to bottom. While assembling the upper frame, the L-shaped mold frames would obstruct the view of the operator so that he cannot check whether the wire of the lamp assembly has shifted or become damaged during the assembly process. Therefore, it is necessary to perform a testing process after completion of the assembly process. This extra step causes the manufacturing yield to be decreased. In order for the backlight module to be stable, the L-shaped mold frames need sufficient width and thickness to be strong. This reduces the view field of the liquid crystal display panel. The width from the edge of the view field of the liquid crystal display panel to the outer edge of the liquid crystal display assembly is extended and cannot be narrowed down. As a result, both of the size and weight of the liquid crystal display device are increased.
With the intention of overcoming the above drawbacks and of producing a lighter, thinner and more stable structure, the present invention is created.